Ron:
I have a old Progressive Electronics 200EP, and a Tempo 77HP/6A. The only 'trick' I ever did was to parallel two 9V batteries to the toner. It seemed to increase the signal.
It's interesting when I come upon a lot of abandoned data/comm on an inspection, that is tagged rather than removed by some LV guys. It's old & well used. I get it from the car, to 'see' if the tags match. Amazing how quick some data guys say.."we will remove it". Truth be they just randomly 'tagged' without any ring-out!
Little do they know that the speaker on the receiver is shot.
